Method for producing stiff fabrics which stand washing



Patented Sept. 9, 1930 UNITED STATES PATENT OFFICE f HEBMANN M'ETLLER, OF HERISAU, SWITZERLAND, ASSIGNOB TO THE F IRM AKTIENGE- SELLSGHAFT CILANDER, OF HERISAU, SWITZERLAND METHOD FOR PRODUCING STIFF FABRICS WHICH STAND WASHING No Drawing. Application filed February 25, 1926, Serial No. 90,707, and in Germany January 21, 1926.

It is already known to produce stiff fabrics by subsequent stifiening, by means of dressings, fabrics made of soft fibres or by utilizing stiff fibrous materials. However both methods of manufacturing stiff fabrics present great disadvantages.

In weaving soft fibrous materials and dressing the fabric thereafter the latter is stiffened, however, the stiffening thus obtained does not stand washing as by washing the fabric stiffened in this manner the dressings are removed to the greatest extent from the fabric and the latter becomes again soft.

With fabrics made of fibrous materials which have a natural stiffness or which have been stiffened during the spinning process and have been woven in the stiffened state, disadvantages present themselves in weaving as it is very difficult to weave stiff yarns.

Moreover the stiff yarns are sometimes brittle and fragile and render it very often impossible to obtain a faultless, uniform, lasting stiff fabric. Fabrics which have been produced with hard finished threads show again the drawback that the stiffened fabric obtained does not stand washing.

It is known to gelatinize superficially vegetable fibres by means of sulfuric acid and to mercerise them under tension. Thereby only a certain degree of stiffness is obtained with vegetable fibres and, if the sulfuric acid is applied in higher concentrations cotton fibres are so changed that they lose their original appearance nearly completely, they agglutina-te and particularly lose their elasticity. The present method permits to overcome the above stated drawbacks. According to the invention the method consists in producing mixed fabrics composed of artificial silk and of other fibres, for instance cotton, and

in subjecting these mixed fabrics for a short time to the action of an inorganic acid, for instance-of sulfuric acid of above B., at

45 ordinary temperatures. The fabric may be bleached, dyed or acid treatment.

Higher concentrations of mineral acids may be used but the temperature must be lower or the time of immersion must be less, or both, and the proper concentration can be readily determined for the instant working conditions by trial under such conditions, but the effect will not be a ood one if the concentration of the acid is elow 45 B.

Whereas in the treatment of cotton with sulfuric acid of the above concentration the cotton shrinks, the surprising effect, has now presented itself that cotton contained in the mixed fabric in combination with artificial silk does not shrink but almost entirely preserves its original character which still shows to advantage in the treated mixed fabric, and nevertheless the fabric shows the desired stiffness.

In a similar manner mixed fabrics composed of artificial silk and of silk, wool, linen and the like may be treated according to the present method.

Any sorts of artificial silk such as viscose silk, nitro-silk, cuprammonium silk, acetate silk and so on may be used.

The degree of stiffness varies according to the nature and to the concentration of the acid, to the duration of the acid treatment as well as according to the proportion of artificial silk contained in the respective mixed fabic. It is advisable to work with cooled aci s.

The nature of the stiffening of the fabrics may be varied by varying the position which the threads of artificial silk occupy in the mixed fabric.

Besides sulfuric acid other inorganic acids may be used, for instance hydrochloric acid, nitric acid, phosphoric acid and the like, as well as mixed acids (such as nitric acid and sulfuric acid).

Pattern effects may be obtained by printing previous to the acid treatment a reserve printed before or after the on certain portions of the fabric which rotects these portions against the action 0 the acid.

Take a mixed fabric of artificial silk and cotton, say, for example, one having the weft as well as the warp composed of alternate rayon and cotton yarns. The fabric is bleached as customary and stretched, preferably both in length and Width. After stretching the goods are passed for about 15 seconds through a sulphuric acid bath of 49"; B. at a temperature of about 10 0., while spread out. The fabric is at once sprayed with cold Water until the wash Water shows no acid reaction. The fabric is then pressed to free it from water, and stretched and dried.

The concentration of the acid may be materially increased if the time and temperature be reduced. .Below 45 B. acid concentration at room temperature, that is to say 10 C. there is no noticeable stiffening, and above 51 under the same conditions the cotton begins to gelatinize and becomes transparent.

The acid stifiens the rayon without materially affecting the cotton either physically or chemically when concentrations below 51 B. are used. Any rayon will stiffen under these conditions, and the degree of stiffening can be regulated by changing any or all of the three variables, concentration, time and temperature.

The mineral acid acts on the rayon more promptly than on the cotton, notwithstanding that both are cellulose products.

I claim:

1. A method for producing stilf fabrics that stand Washing, which consists in manufacturing a mixed fabric composed of artificial silk fibres and of other fibres, and subjecting the mixed fabric to the action of an inorganic acid until the desired stiffening of the artificial silk is obtained, leaving the vegetable fibres soft and pliabl 2. A method for producing stiff fabrics that stand Washing, which consists in manufacturing a mixed fabric composed of artificial silk fibres and other fibres and subjecting the mixed fabric to the action of a cooled inorganic acid until the desired stiffening of the artificial silk is obtained, leaving the vegetable fibres soft and pliable.

3. A method for producing stiff fabrics that stand washing, which consists in manufacturing a mixedfabric composed of artificial silk fibres and of vegetable fibres, and subjecting the mixed fabric to the action of an inorganic acid at atmospheric temperature until the desired stiffening of the artificial silk is obtained, leaving the vegetable fibres soft and pliable.

4. A stifi fabric that stands washing comprising a mixed fabric containing stiffened artificlal silk and substantially unstiifened admixed threads.

5. The method of producingstiif, washable fabrics, which comprises manufacturing a mixed fabric containing artificial silk, and subjecting the fabric to the action of mineral acid, the concentration of the acid, the duration and temperature at which the fabric is subjected to said acid being such as to harden the artificial silk without materially affecting the other constituents of the fabric.

In testimony whereof, I have signed my name to this specification.

HERMANN MULLER. 

